Who knows. But what we do know is that there are lots of questions about Outlook.com. Here are the answers to some of the most pressing.

I use Hotmail now. What happens to my email? The next time you open Hotmail, you may see the new interface.

If you don't, you can switch by choosing "Upgrade to Outlook.com" from the Options menu in the upper right when you're at your inbox.

How do I get one of the new Outlook.com addresses? For a brand new account, go to Outlook.com. (You may need to log out if you've already used the new site, then return to Outlook.com.) Start the process by clicking the "Sign up" button on the left. Fill in the form, which includes a field for your new xxxxxoutlook.com address, complete the CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart") and click the "I accept" button at the bottom.

What does it look like? Very Metro. The user interface (UI) has the same flattened, color-subdued look as a Metro app in Windows 8. By comparison, the traditional Hotmail UI looks like a carnival ... busy, garish, loud, cheap.

Obviously, Outlook.com's UI will mesh well with Windows 8. Depending on your opinion of that UI, however, it may seem jarring on older or non-Microsoft OSes, including Windows 7 and OS X.

Can I keep my old address and still use Outlook.com? Yes, you can.

You can keep Microsoft-related addresses ending with hotmail.com, msn.com and live.com while switching to the new UI.

I want to ditch my hotmail.com address. How do I do that? Start at Outlook.com. If you're not automatically pushed to the new UI, switch by choosing "Upgrade to Outlook" from the Inbox's Options menu -- and select "More mail settings" from the gear icon's menu. Click on "Rename your email address."

Enter your existing hotmail.com address -- the portion to the left of the @ character -- and click Save while "outlook.com" is visible in the drop-down list. If the address is already taken, you'll see a message to that effec

Does Outlook.com show me ads? Yes, it does. Text-based ads, to be specific.

If you want an ad-free screen, you have to fork over $19.99 annually for what's still called "Hotmail Plus." According to Microsoft, subscribing to Plus keeps ads off Hotmail and Outlook while they operate side-by-side.

Will Microsoft force me to use Outlook.com? At some point, yes.

There's no public timeline, but Microsoft said that when it wraps up the preview, "we will upgrade [users] to Outlook."

We expect that even after the preview ends, former Hotmail users -- perhaps identified by their account addresses -- will be able to access a "classic" UI for some length of time. That's been Microsoft's practice in the past when it's made drastic changes to the look of Hotmail.

How much SkyDrive space do I get? All new Outlook.com accounts receive the SkyDrive-standard 7GB storage allotment.

Migrating or upgrading an existing Hotmail account doesn't boost the storage on your already-in-place SkyDrive by that amount, however; you get bupkis in that scenario.

I love Gmail, want to try Outlook.com, but don't need another email address. How do I proceed? Sorry, you can't avoid the new address.

No surprise -- Outlook.com takes direct aim at Google's Gmail -- Microsoft's published a short list of steps to forward your Gmail messages to Outlook.com, link Gmail contacts to the new Microsoft service and even set Outlook to send messages from your Gmail address.

Can I use Outlook.com on my smartphone or tablet? Yes. Microsoft has posted instructions for adding an Outlook account to an Android, iOS or Windows Phone device here.

Can Outlook.com sync my mail to another PC or my smartphone? Yes. The new service relies on Exchange ActiveSync to synchronize not only email but also calendars and contacts.

ActiveSync was developed for mobile sync, so it's no shock that the technology synchronizes data between Outlook.com and various devices, including those powered by Android, iOS and Windows Phone. Outlook also syncs with Outlook 2013, the email client that's part of the Office 2013 suite, which was released as a preview last month. It also synchronizes with the Metro-ized Mail app in Windows 8, although you'll have to add your new Outlook.com to the app.

Some are out of luck, though: Mac users running the Entourage or Outlook 2011 clients can't sync their mail with Outlook.com. Nor can users of OS X's own Mail client.